Method and apparatus for feeding multi-sheet documents

ABSTRACT

A feed mechanism for the singulation and delivery of multi-sheet documents. The feed mechanism includes a support surface for receiving a stack of multi-sheet documents, a conveyor mechanism for transporting a lowermost document of the multi-sheet document stack and a restraint assembly defining an opening for the passage of the lowermost document. The restraint assembly is, furthermore, operative to retard the motion of documents disposed above the lowermost document during singulation and delivery thereof. The feed mechanism is characterized by a contour generator disposed in combination with the support surface which contour generator is operative to generate an arcuate cross section in connection with the stack of multi-sheet documents during singulation and delivery. The arcuate cross-sectional shape is disposed a plane orthogonal to the feed path of the multi-sheet documents.

TECHNICAL FIELD

This invention relates to feed mechanisms and, more particularly, to a new and useful method and apparatus for feeding/singulating multi-sheet documents for use in sheet handling equipment such as printing apparatus.

BACKGROUND ART

Feed mechanisms or modules are commonly employed to supply printers with various size media for printing. One such feed mechanism, to which the present invention is directed, is a feeder for supplying multi-sheet documents such as newspapers and magazines to a printing apparatus. Such documents may be fed to print mailing address information on a face sheet of the multi-sheet document.

FIG. 1 depicts a typical feed mechanism 100 for feeding multi-sheet documents 110 to a printing apparatus 112. Therein, a plurality of newspaper documents 110 are stacked upon a support surface 114 of the feed mechanism 100 with a re-curved fold portion 110F of the document being fed first into the printing apparatus 112. The stack of newspaper documents 110 is fed from the bottom of the stack and singulated by the combined action of transport rollers/belts 116 and a restraint assembly 118. The transport rollers/belts 116 are disposed beneath the lowermost document to urge the document forward toward the printer entrance 112E. The restraint assembly 118 is spatially positioned to keep all but one of the stack 110 from passing through and entering the printer 112. That is, the restraint assembly 118 retards the passage of documents 110U residing above the thickness of a single document 110. Generally, the restraint assembly 118 is calibrated or set by passing a single document between the rollers/belts 116 and positionable elements of the restraint assembly 118 to define the required thickness.

To assist the gravity feed and lower the surface friction, it is common to incorporate a plurality of linearly aligned wedges 120 along the support surface 114 of the feed mechanism 110. The wedges 120 produce an inclined surface 122 to produce a gravity-assisting downward force on the stack 110 while additionally reducing the surface area in contact with the support surface 114. With respect to the latter, it will be appreciated that the wedges 120 raise the lowermost document 110L away from the support surface 114 thereby reducing surface friction.

While feed mechanisms 100 are most reliable for feeding single sheet documents, greater difficulty has been experienced when feeding multi-sheet documents. For example, the predetermined thickness dimension between the rollers/belts 116 and restraint assembly 118 must be precisely controlled to ensure that a multi-sheet document is properly singulated before entering the printing device 112E. That is, should the thickness dimension deviate from the optimum position, there is a propensity for the multiple sheets to separate and roll open about the fold line. That is, the upper restraint assembly 118 may prevent the upper sheets from sliding past the opening while the lower sheets move at the rate of the lower belts 116 of the conveyor. The difference in feed rate between the upper and lower sheets can cause the multi-sheet document 110 to separate about the fold line 110F and jam when entering the printing apparatus 112. Consequently, painstaking trial and error may be required to achieve the optimal opening to facilitate singulation of multi-sheet documents 110.

A need, therefore, exist for a feed mechanism which is less reliant upon the dimensional characteristics of the print feed opening, and reliably singulates multi-sheet documents for feeding the same to printing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate presently preferred embodiments of the invention and, together with the general description given above and the detailed description given below serve to explain the principles of the invention. As shown throughout the drawings, like reference numerals designate like or corresponding parts.

FIG. 1 a is a side view of a prior art feed mechanism including a stack of multi-sheet documents supported along a leading edge by a conveyor assembly and along a trailing edge by a linear array of angle wedges.

FIG. 1 b is a top view of the prior art feed mechanism shown in FIG. 1 a to more clearly illustrate the linear array of angle wedges, the conveyor assembly and a restraint assembly for singulating the lowermost document of the multi-sheet stack.

FIG. 1 c is a cross sectional view taken substantially along line 1 c-1 c of FIG. 1 a wherein the stack of multi-sheet documents produces a linear cross section along a plane orthogonal to the feed path of the multi-sheet documents.

FIG. 2 a is a side view of the feed mechanism according to the present invention including a stack of multi-sheet documents supported along a leading edge by a conveyor assembly and along a trailing edge by a contour generator which produces a favorable cross sectional shape for singulating a lowermost multi-sheet document to a printing apparatus.

FIG. 2 b is a top view of the inventive feed mechanism shown in FIG. 2 a illustrating one embodiment of the contour generator for singulating multi-sheet documents.

FIG. 2 c is a cross sectional view taken substantially along line 2 c-2 c of FIG. 2 a wherein the contour generator produces an arcuate cross section in a plane orthogonal to the feed path of the multi-sheet documents.

FIG. 3 a is a top view of an alternate embodiment of the contour generator including an array of angle wedges disposed to each side of a plane parallel to the feed path of the multi-sheet documents and bifurcating the support surface of the inventive feed mechanism.

FIG. 3 b is a side view of the contour generator shown in FIG. 3 a wherein the slope of an angle wedge increases as the wedge approaches the central bifurcating plane.

FIG. 3 c is a side view of an alternative

SUMMARY OF THE INVENTION

A feed mechanism is provided for singulation and delivery of multi-sheet documents along a feed path. The feed mechanism includes a support surface for receiving a stack of multi-sheet documents, a conveyor mechanism for transporting a lowermost document of the multi-sheet document stack and a restraint assembly defining an opening for the passage of the lowermost document. The restraint assembly is, furthermore, operative to retard the motion of documents disposed above the lowermost document during singulation and delivery thereof. The feed mechanism is characterized by a contour generator disposed in combination with the support surface which contour generator is operative to generate an arcuate cross section in connection with the stack of multi-sheet documents during singulation and delivery. The arcuate cross-sectional shape is disposed a plane orthogonal to the feed path of the multi-sheet documents.

DETAILED DESCRIPTION

The present invention is described in the context of a mechanism for feeding multi-sheet documents to a printing apparatus. While the print feed mechanism is useful for feeding singulated documents to a device for printing delivery or address information on a face sheet of the multi-sheet document, it will be appreciated that the invention is broadly applicable to any mechanism for feeding multi-sheet documents to any material/sheet handling device. For example, devices receiving multi-sheet documents may include collation, sortation and/or mailpiece handling equipment. Hence, the described embodiment is intended to exemplify a feed mechanism and/or adaptation thereof which highlights the teachings and advantages of the present invention.

In the broadest sense of the invention, the feed mechanism is adapted to support a stack of multi-sheet documents so as to produce a favorable cross-sectional shape. The cross-section is in a plane orthogonal to the feed path of the multi-sheet stack and is operative to enhance the handling qualities of documents during delivery and singulation. More specifically, the feed mechanism includes a contour generator disposed beneath the multi-sheet stack to effect an arcuate cross sectional shape. Furthermore, the arcuate shape is effected by the weight of the stack and force due to gravity. The arcuate cross section forms a shallow U-shape which enhances the stiffness of each individual document while, at least in part, increasing the frictional forces between individual sheets of the multi-sheet document.

In the described embodiment, the inventive feed mechanism 6, shown in FIGS. 2 a and 2 b, singulates a stack 10 of multi-sheet documents 10S for delivery to a print apparatus 12. In FIG. 2 b, the stack 10 is shown in phantom lines to view the relevant underlying elements/structure. A plurality of multi-sheet documents 10S are stacked upon a support surface 14 of the feed mechanism 6 such that a folded edge 10F of the document is fed into the print apparatus 12. The documents 10S are fed from the bottom such that the lowermost document 10L in the stack is singulated and fed by a system of conveyor rollers/belts 16 to the entrance of the print apparatus 12.

Similar to methods employed in prior art feed mechanisms, a restraint assembly 18 is employed to inhibit all but the lowermost document 10L from being delivered to the print apparatus 12. That is, the restraint assembly 18 is spatially positioned retard the movement or passage of documents 10U residing above the lowermost document 10L. The restraint assembly 18 may be any device which defines an opening, i.e., between the restraint assembly 18 and the conveyor 16, for the passage of a single multi-sheet document. In the described embodiment, the restraint assembly 18 includes a positionable gate/finger 18R which rides or slides in a vertical track 18T. The gate 18R is vertically positioned within the track 18T to define an opening OR suitable for the passage of the lowermost multi-sheet document 10L.

In FIGS. 2 b and 2 c, the feed mechanism 6 includes a contour generator 20, disposed in combination with the support surface 14, adapted to produce an arcuate cross-section (see FIG. 2 c) in a plane orthogonal to the feed path FP of the multi-sheet documents 10S. The stack of documents 10S is compiled and laid over the contour generator 20 such that, under the weight/force of gravity, an arcuate or shallow-U shape is produced (best seen in FIG. 2 c). In the described embodiment, the contour generator 20 comprises pairs of angle wedges 24P1, 24P2 disposed along and coupled by a central shaft 26. Each pair of angle wedges 24P1, 24P2 is disposed on opposing sides of a central bifurcating plane BP (see FIG. 2 b) which bisects the support surface 14 and is parallel to the feed path FP of the documents 10S. Furthermore, the angled wedges 24P1, 24P2 are directed inwardly toward the central bifurcating plane BP to produce a trough and, consequently, the arcuate or U-shaped contour of the stacked documents 10. Furthermore, the angle wedges 24P1, 24P2 support a trailing edge portion 10T of the stack 10 such that the depth of the arc or rate of change thereof gradually decreases from the trailing edge portion 10T to the leading edge fold 10F of the stack 10S. Consequently, the U-shaped cross section transitions from a deep to shallow contour from the trailing to leading edge of the stack 10S.

In the described embodiment, the wedges 24P1, 24P1 define inclined surfaces 28 to produce a slope ranging from about thirty-five (35) to about sixty (60) degrees relative to a horizontal plane. Though, the inclination or slope of the surfaces 28 will also depend, inter alia, on factors such as (i) the position or distance of each angled wedge from the central bifurcating plane BP, (ii) its angle relative to the feed path FP (shown as angle θ in FIG. 2 b) and (iii) the stiffness and thickness of each multi-sheet document 10S.

The support surface 14 of the feed mechanism 6 may include a central slot 30 to provide a means for adjusting the location and contour of the stack 10S relative to the entrance area or opening OR for accepting each multi-sheet document 10S. In FIG. 2 b, the shaft 26 may include a central fitting 32 for accepting a set screw or knob which engages the slot 30. The contour generator 20 may be moved forward or aft along the feed path FP to alter or adjust the presentation of the stack 10S. Furthermore, the central fitting 32 is detachable from the underlying support surface 14 so that other documents, e.g., single sheet, mailpieces, postcards, etc., may be fed when there is no requirement for the contour generator 20.

In FIGS. 3 a and 3 b an alternate embodiment of the invention is depicted wherein the contour generator 20 includes an array of right-angle wedges 24A, 24B and 24C disposed to each side the central bifurcating plane BP. The right-angle wedges 24A, 24B and 24C are connected by a central linear shaft, however, the base of each right-angle wedge varies in length. Furthermore, while the height of each of the wedges 24 a, 24 b, 24C remains constant, the slope of each of the wedges 24A, 24B, 24C varies depending upon its proximity to the central bifurcating plane BP. Stated in another manner, as the wedges 24A, 24B, 24C are more distally spaced from the central bifurcating plane, the slope of the respective hypotenuse decreases. As such, a stack of multi-sheet documents 10S which is laid upon and supported by this array of right-angle wedges 24A, 24B, 24C will produce an arcuate contour or cross-sectional shape similar to that shown in FIG. 2 c.

In FIG. 3 c yet another alternate embodiment of the invention is depicted wherein the base and height of the right-angle wedges 24A, 24B and 24C varies such that similar triangles are produced. Furthermore, as the distance from the bifurcating plane BP increases, the size of the wedges 24A, 24B, and 24C increase proportionally. That is, the base and height increase by equal percentages from wedge 24C which is nearest to the plane BP to wedge 24A which is farthest from the plane. As such, a stack of multi-sheet documents 10S laid upon and supported by this array of right-angle wedges 24A, 24B, 24C produces an arcuate contour/cross-sectional shape similar to that shown in FIG. 2 c.

While the contour generator 20 has been described and depicted in terms of a plurality of connected wedges, it will be appreciated that other structures and shapes can effect a similar arcuate shape in connection with a stack of multi-sheet documents 10S. The arcuate shape enhances the handling qualities of such multi-sheet documents during singulation and delivery to other material/sheet handling equipment. Specifically, the arcuate cross section enhances the stiffness of each individual document while, at the same time, increasing the frictional forces between individual sheets of the multi-sheet document.

Although the invention has been described with respect to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and various other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention. 

1. A feed mechanism for singulation and delivery of multi-sheet documents along a feed path, comprising: a support surface for receiving a stack of multi-sheet documents; a conveyor mechanism disposed along the support surface for transporting a lowermost document of the multi-sheet document stack; a restraint assembly disposed above the conveyor and defining an opening therebetween for the passage of the lowermost document, the restraint assembly, furthermore, operative to retard the motion of documents disposed above the lowermost document during singulation thereof; and a contour generator disposed in combination with the support surface and operative to generate an arcuate cross section in connection with the stack of multi-sheet documents during singulation and delivery, the cross section disposed a plane orthogonal to the feed path of the multi-sheet documents.
 2. The feed mechanism according to claim 1 wherein the contour generator is includes at least two angle wedges disposed on opposing sides of a central bifurcating plane, the angle wedges defining inclined surfaces disposed inwardly toward the bifurcating plane.
 3. The feed mechanism according to claim 1 wherein the contour generator includes a plurality of angle wedges, wherein each of the angle wedges defines an inclined surface having a slope, and wherein the slope of each angle wedge varies along a length of the shaft.
 4. The feed mechanism according to claim 1 wherein the support surface defines a central bifurcating plane, wherein contour generator includes a plurality of angle wedges each defining a base and height dimension, and wherein the base and height dimension increase proportionally from a location proximal to the bifurcating plane to a location distal from the bifurcating plane.
 5. The feed mechanism according to claim 2 wherein the angle wedges are connected by a shaft and wherein the connecting shaft is detachably mounted to the support surface.
 6. The feed mechanism according to claim 3 wherein the angle wedges are connected by a shaft and wherein the connecting shaft is detachably mounted to the support surface.
 7. The feed mechanism according to claim 4 wherein the angle wedges are connected by a shaft and wherein the connecting shaft is detachably mounted to the support surface.
 8. The feed mechanism according to claim 2 wherein the angle wedges have an inclined surface defining an angle relative to a horizontal plane, the angle ranging from about thirty-five (36) degrees to about sixty (60) degrees.
 9. A method for singulation and delivery of multi-sheet documents along a feed path, comprising: receiving a stack of multi-sheet documents along a support surface; supporting the multi-sheet stack along the support surface so as to generate an arcuate cross section in a plane orthogonal to the feed path of the multi-sheet documents. conveying a lowermost document of the multi-sheet document stack along the support surface; and restraining the motion of documents disposed above the lowermost document during singulation and delivery of the lowermost document.
 10. The method according to claim 9 wherein the step of supporting the multi-sheet stack is performed by providing a contour generator having at least two angle wedges disposed on opposing sides of a central bifurcating plane, the angle wedges defining inclined surfaces disposed inwardly toward the bifurcating plane.
 11. The method according to claim 9 wherein the step of supporting the multi-sheet stack is performed by providing a contour generator having a plurality of angle wedges, each of the angle wedges defining an inclined surface having a slope, and the slope of each angle wedge varying along a length of the shaft
 12. The method according to claim 9 wherein the step of supporting the multi-sheet stack is performed by providing a contour generator having a plurality of angle wedges each defining a base and height dimension, the base and height dimension increasing proportionally from a location proximal to a central bifurcating plane to a location distal from the bifurcating plane.
 13. A contour generator for the singulation and delivery of multi-sheet documents along a feed path, the multi-sheet documents being fed as a stack along a support surface of a feed mechanism, the contour generator comprising: a connecting shaft detachably mounting to the support surface; a plurality of angle wedges disposed along and mounting to the connecting shaft, the angle wedges adapted to generate an arcuate cross section in connection with a stack of multi-sheet documents during singulation and delivery, the cross section disposed a plane orthogonal to the feed path of the multi-sheet documents.
 14. The contour generator according to claim 13 wherein at least two angle wedges are disposed on opposing sides of a central bifurcating plane, the angle wedges defining inclined surfaces disposed inwardly toward the bifurcating plane.
 16. The contour generator according to claim 13 wherein each of the angle wedges defines an inclined surface having a slope, and wherein the slope of each angle wedge varies along a length of the connecting shaft.
 17. The contour generator according to claim 14 wherein the angle wedges each define a base and height dimension, and wherein the base and height dimension increase proportionally from a location proximal to the bifurcating plane to a location distal from the bifurcating plane.
 18. The contour generator according to claim 13 wherein the connecting shaft is detachably mounted to the support surface.
 19. The contour generator according to claim 14 wherein the connecting shaft is detachably mounted to the support surface.
 20. The contour generator according to claim 13 wherein the angle wedges have an inclined surface defining an angle relative to a horizontal plane, the angle ranging from about thirty-five (36) degrees to about sixty (60) degrees. 